However, to avail IndiGo's the discount offer, one has to book tickets at least 15 days prior to the date of departure.

IndiGo is also offering an additional 20% cashback if passengers pay with American Express, RBL Bank

IndiGo has extended its ongoing Valentine's Day sale till February 14, 2019, said the private carrier in a press release on Thursday. Under the offer, IndiGo is offering domestic and international flight tickets starting from an all-inclusive Rs. 899 and Rs. 3,399, respectively. The airline is also offering an additional 20 per cent cashback if passengers pay with American Express, RBL Bank or Mobikwik wallet. However, to avail the discount offer, one has to book tickets at least 15 days prior to the date of departure.

Under the sale offer, the airline is offering flight tickets on Delhi-Ahmedabad route starting at Rs. 1,999. Flight tickets from Delhi to Bengaluru are priced at Rs. 2,699. Similarly, tickets from Delhi to Bagdogra and Chandigarh are priced at Rs 2,699 and Rs 1,199, respectively.

The discount offer cannot be clubbed with any other offer and is not applicable on group bookings, said IndiGo. The offer is valid only on non-stop flights on various sectors across the IndiGo's network, noted the carrier. However, the discount is not applicable on airport charges and government taxes.

IndiGo's offer on flight tickets comes amid high competition in the country's civil aviation sector where airlines are coming up with discount offers and new routes on a daily basis to attract passengers. Last month, IndiGo announced Istanbul as its 16th international destination. The airline will operate daily direct flights on the Delhi-Istanbul route from March 20, 2019.

Meanwhile, SpiceJet is also offering domestic and international flight tickets starting from an all-inclusive Rs. 899 and Rs. 3,699, respectively, which is valid till February 14.